The Conversation: Tim Lang, professor of food policy

Lang says: 'There is too much food in the world, not too little: more of us overweight than underweight, overconsumption in the West and under-consumption in the developing world' (Alastair Levy)

What did you have for breakfast?

Organic porridge over at least two bits of fruit, and a cup of tea.

Do you grow your own vegetables?

We do, in our garden, but we don't live off them – that would be impossible.

Britain has been hit by several food crises – farming crisis, the horsemeat scandal, rising food poverty, an obesity crisis. When did it all go wrong?

Two hundred years of 'progress' were achieved by mining our ecosystems. The modern world of food is messy – problems of over-consumption, under-consumption and mal-consumption.

What worries you more about our diets: people eating too much or people not eating enough?

Both result from a food culture that is mismatched to our ecosystem. There is too much food in the world, not too little: more of us overweight than underweight, overconsumption in the West and under-consumption in the developing world.

You coined the term 'food miles'. What's the big new idea we should be talking about?

'Ecological public health'; the idea that public health depends on the health of our ecosystems.

Can you be a conscientious consumer on a tight budget?

There are many studies to show that people on low incomes are no different in their range of values to rich people. They just lack the conditions to deliver it. We're not helping people to live healthily. I can't walk to Clapham Junction station from where I live without going past 30 or 40 takeaway places saying: 'Come and buy food from me, have a quick fix'.

You've never enjoyed a Big Mac?

I believe the second-ever McDonald's in Britain was in the West End. I went there in the 1970s, ate a Big Mac – that was the last time.

How did it taste?

Like a greasy hamburger.

I can confirm that it tastes exactly the same now.

To have a burger once a month, no problem. But to have a burger and French fries every day, bad news. The problem with a burger-and-cola diet is that it damages biodiversity. You can guarantee the meat would have been fed on grain. We have to reverse this 'meat culture' fixation.

Would it solve a lot of problems if the entire Western world went vegetarian?

Depends how the vegetables are grown. But it would help if we could put animals back into their ecological niche. Precious land, water and fertiliser is spent growing grain, 50 per cent of which goes to animals that are inefficient converters of energy.

What is your favourite dish?

Porridge. Everyone should have a good breakfast that doesn't give them a sugar rush or make them buy imported corn covered in sugar.

I had bagels for breakfast – how about them?

They're lovely. But I bake my own bread.